Correlation of Histopathological Findings With Radiation Exposure Levels After Y90 Transarterial Radioembolization (TARE) of Hepatic Metastases: A Feasibility Study

Inclusion Criteria: * age ≥ 18 years * Eastern Cooperative Oncology Group (ECOG) performance status 0-2 * histologically confirmed primary adenocarcinoma of the colon or rectum * CLM considered unresectable or not amenable to percutaneous ablation * existent tissue samples from a standard of care biopsy of the target tumor within 42 days prior to treatment OR clinical indication for biopsy at the time of the treatment under the institutional guidelines for progression of disease. * adequate blood cell counts (WBC \> 1.5 x 109/L, platelet count \> 50 x 109/L) * adequate renal function (creatinine \< 1.5 mg/dL) * total bilirubin level ≤ 1.5 mg/dL Additional inclusion criteria for patients, undergoing 90Y radiation segmentectomy: A. patients not amenable to surgery or thermal ablation Exclusion Criteria: Study exclusion criteria will be similar to general TARE exclusion criteria, which are as follows: * prior hepatic radiotherapy (The lesion / lobe being treated cannot have had prior treatment with radiotherapy - untreated lesions / lobes in the liver may be evaluated under the protocol) * severe cirrhosis * severe portal hypertension * uncorrectable flow to the gastrointestinal tract and/or \>30 Gy (or \>50 Gy in multiple sessions) radiation absorbed dose to the lungs All patients with liver-dominant disease will be considered candidates for TARE even in the face of oligometastatic (up to 5 sites) extrahepatic disease, that is stable or controlled by chemotherapy.